The Hydromax Series is another amazing penile enhancement device from the masterminds at Bathmate. This pump's unique design offers a number of nifty features not found in other penis pumps. The most novel aspect of this pump is the fact that it uses water, instead of air, to create suction. This means increased comfort as well as a more powerful vacuum. Speaking of comfort, this pump comes with a soft comfort insert that creates a tight seal without any discomfort you get with some penis pumps.